KOCHI: With the breakneck speed of expansion of cities, India has the greatest number of urban-dwellers in the world without safe, private toilets and practising open defecation though the government has made sanitation a priority, a report by a global NGO says. 

"India ranks top for having the greatest number of urbanites living without a safe, private toilet-- 157 million - as well as the most urban dwellers practising open defecation-- 41 million," the report by WaterAid, a UK-based charity working in the field of safe water and sanitation, says. 

The second annual analysis of world's toilets 'Overflowing Cities The State of the World's Toilets 2016', released on the eve of World Toilet Day being observed tomorrow this year, also says the high population density of urban areas means that diseases spread fast in the absence of good sanitation. 

The report says the problem was so big that the daily waste produced on the streets of India's towns and cities was enough to fill eight Olympic-sized swimming pools, or 16 jumbo jets with poo every day. 

Noting that the country was going through the largest rural-to-urban migration of this century, it says Prime Minister Narendra Modi's Swachh Bharat (Clean India) campaign recognises the country's health and wealth largely depends on towns and cities growing in a sustainable, equitable way. 

"In today's India, 381 million people - a population roughly the size of Western Europe - live in rapidly expanding urban areas, and 157 million of those people have nowhere decent to go to the toilet," it says. 

Even though the government has made sanitation a priority, the numbers of urbanites living without sanitation has swelled by 26 million since year 2000 as cities expand at breakneck speed, the report, which examined the problems facing more than 700 million urban dwellers around the world living without decent sanitation, says. 

An estimated 100 million of these have no choice but to defecate in the open-- using roadsides, railway tracks and even plastic bags, dubbed 'flying toilets'. 

WaterAid's Director of Programmes & Policy, Avinash Kumar, said India's rapid and unplanned urbanisation has resulted in various developmental challenges. 

"... Current rates of urbanisation and meeting the increasing demand for basic services may make achieving Sustainable Development Goals a problem," he said. 

Kumar said there was a vital need for an integrated approach towards urban planning that prioritises provision of basic services like clean water, safe sanitation and sustainable faecal sludge management by ensuring people's participation. 

"This is the only way to create a healthier and more sustainable future," he said.